AMD GPU Material in "material preview mode" and "rendered mode", is entirely gray as background. Only outline is displayed
Update: Blender 2.92.0, 2.91.1 and 2.83.11 will contain workarounds for the missing / incorrectly rendered surfaces of mesh, curves and metaballs as well as the incorrectly rendered wireframes caused by bugs in the graphics driver.

The graphics driver version Adrenalin 2020 Edition 20.11.2 and later appear to cause issues for several users, as reported in T82856 and related tickets. Installing a previous driver version should solve these problems until the bug in the driver is fixed or Blender provides a workaround for the problem.